Ponded - A condition in which water stands in a closed depression. Water may 

 be removed only by percolation, evaporation, and/or transpiration. 



Poorly drained - Soils that commonly are wet at or near the surface during a 

 sufficient part of the year that field crops cannot be grown under natural 

 conditions. Poorly drained conditions are caused by a saturated zone, a layer 

 with low hydraulic conductivity, seepage, or a combination of these 

 conditions. 



Population - A group of individuals of the same species that occurs in a given 

 area. 



Positive wetland indicator - Any evidence of the presence of hydrophytic 

 vegetation, hydrlc soil, and/or wetland hydrology in an area. 



Prevalent vegetation - The plant community or communities that occur in an 

 area during a given period. The prevalent vegetation is characterized by the 

 dominant macrophytic species that comprise the plant community. 



Quantitative - A precise measurement or determination expressed numerically. 



Range - As used herein, the geographical area in which a plant species is 

 known to occur. 



Redox potential - A measure of the tendency of a system to donate or accept 

 electrons, which is governed by the nature and proportions of the oxidizing 

 and reducing substances contained in the system. 



Reducing environment - An environment conducive to the removal of oxygen and 

 chemical reduction of ions in the soils. 



Relative density - A quantitative descriptor, expressed as a percent, of the 

 relative number of individuals of a species in an area; it is calculated by 



Number of individuals of species A ^ j„„ 



Total number of individuals of all species 



Relative dominance - A quantitative descriptor, expressed as a percent, of the 

 relative size or cover of individuals of a species in an area; it is 

 calculated by 



Amount* of species A ^ ._„ 

 Total amount of all species 



Relative frequency - A quantitative descriptor, expressed as a percent, of the 

 relative distribution of individuals of a species in an area; it Is calculated 

 by 



Frequency of species A ^ . „ „ 



Total frequency of all species 



* The "amount" of a species may be based on percent areal cover, basal area, 

 or height. 



AlO 



